Recent developments in zeolite catalysts and hydrocarbon conversion processes have created interest in utilizing olefinic feedstocks for producing C.sub.5 + gasoline, diesel fuel, etc. In addition to the basic work derived from ZSM-5 type zeolite catalysts, a number of discoveries have contributed to the development of a new industrial process, known as Mobil Olefins to Gasoline/Distillate ("MOGD"). This process has significance as a safe, environmentally acceptable technique for utilizing feedstocks that contain lower olefins, especially C.sub.2 -C.sub.5 alkenes. U.S. Pat. Nos. 3,960,978 and 4,021,502 (Plank, Rosinski and Givens) disclose conversion of C.sub.2 -C.sub.5 olefins, alone or in admixture with paraffinic components, into higher hydrocarbons over crystalline zeolites having controlled acidity. Garwood et al have also contributed improved processing techniques to the MOGD system, as in U.S. Pat. Nos. 4,150,062 4,211,640, and 4,227,992. The above-identified disclosures are incorporated herein by reference.
Conversion of lower olefins, especially propene and butenes, over HZSM-5 is effective at moderately elevated temperatures and pressures. The conversion products are sought as liquid fuels, especially the C.sub.5 + aliphatic and aromatic hydrocarbons. Olefinic gasoline can be produced in good yield by the MOGD process and may be recovered as a product or recycled to the reactor system for further conversion to distillate-range products. Operating details for typical MOGD units are disclosed in copending U.S. patent applications Ser. No. 488,834, filed Apr. 26, 198 (Owen et al), now U.S. Pat. No. 4,456,779 and Ser. No. 481,704, filed Apr. 4, 1983 (Tabak), incorporated herein by reference.
In addition to their use as shape selective oligomerization catalysts, the medium pore ZSM-5 type catalysts are useful for converting methanol and other lower aliphatic alcohols and/or corresponding ethers to olefins. Particular interest has been directed to a catalytic process for converting low cost methanol to valuable hydrocarbons rich in ethene and lower alkenes. Various processes are described in U.S. Pat. No. 3,894,107 (Butter et al), U.S. Pat. No. 3,928,483 (Chang et al), U.S. Pat. No. 4,025,571 (Lago), U.S. Pat. No. 4,506,106 (Hsia et al), and U.S. Pat. No. 4,579,999 (Gould et al). Significance of the methanol-to-olefins ("MTO") type processes, especially for producing ethene, is discussed in Hydrocarbon Processing, Nov. 1982, pp. 117-120.